Nitrogen refining and purifying device and process

Abstract

The invention discloses a device and a process for refining and purifying nitrogen, and relates to the technical field of nitrogen purification, and the process comprises the following steps: step 1, desulfurization pretreatment: feeding a raw material common nitrogen from a nitrogen inlet, and removing sulfides such as H2S and SO2 through a desulfurization tower; step 2, TSA deep decarburization: the desulfurized nitrogen enters a decarburization tower A or a decarburization tower B which is working, and CO2, CO and hydrocarbon are deeply removed; and 3, purity monitoring and output: detecting the purified nitrogen through an analyzer to generate qualified high-purity nitrogen, outputting the qualified high-purity nitrogen, and automatically emptying the qualified high-purity nitrogen if the qualified high-purity nitrogen is not qualified. By inheriting a double-tower composite process of normal-temperature desulfurization and temperature swing adsorption and introducing online monitoring and automatic control, deep, continuous and stable removal of various impurities such as carbon monoxide, carbon dioxide and sulfide in nitrogen is realized, and the problems that an existing purification device is single in function, cannot deeply remove various harmful impurities and is low in purification efficiency are solved. And a continuous operation and real-time quality assurance mechanism is lacked.

Description

Technical Field

[0001] This invention relates to the field of nitrogen purification technology, specifically to a nitrogen refining and purification apparatus and process. Background Technology

[0002] Nitrogen purification refers to the removal of impurities from nitrogen using physical or chemical methods. Industrially, it mainly removes oxygen from nitrogen to improve its purity. Nitrogen has the highest content in the atmosphere, but different industries have very different requirements for nitrogen purity, thus requiring purification equipment.

[0003] Compared with existing purification devices, the following defects still exist: conventional purification devices have a single function, resulting in incomplete purification. They cannot perform differentiated and efficient removal based on the physicochemical properties of impurity molecules, and lack real-time quality monitoring, leading to large fluctuations in product quality. At the same time, continuous production is difficult, resulting in low efficiency. Existing purification devices have poor equipment coupling, making upgrades and modifications difficult, and adsorbent regeneration is difficult and costly. Summary of the Invention

[0004] The purpose of this invention is to provide a nitrogen purification device and process to solve the following technical problems: existing purification devices have limited functions, cannot deeply remove various harmful impurities, and lack continuous operation and real-time quality assurance mechanisms.

[0005] The objective of this invention can be achieved through the following technical solutions: A nitrogen refining and purification process includes the following steps: Step 1, Desulfurization Pretreatment: Ordinary nitrogen gas enters from the nitrogen inlet and passes through the desulfurization tower to remove sulfides such as H2S and SO2; Step 2, TSA deep carbon removal: The nitrogen gas after desulfurization enters the working carbon removal tower A or carbon removal tower B for deep removal of CO2, CO, and hydrocarbons; Step 3, Purity Monitoring and Output: The purified nitrogen is tested by an analyzer. If qualified high-purity nitrogen is generated, it is output. If it is not qualified, it is automatically vented. Step 4, Regeneration Purging and Heating: A portion of the nitrogen gas is drawn out and passed through a flow meter and heater to generate high-temperature regenerated nitrogen gas; Step 5, thermal purging and impurity desorption: High-temperature regenerated nitrogen gas is introduced in reverse into saturated carbon removal tower A or carbon removal tower B, and the desorbed impurities are carried out by heating. Step 6, Cooling and System Reset: The hot regenerated nitrogen containing impurities needs to be cooled by a cooler and then filtered by a filter. Finally, it is pressurized by a booster and then recycled or vented using a vent valve.

[0006] As a further aspect of the present invention: the cooler is composed of a lower shell and an upper shell, and the connection between the lower shell and the upper shell is threaded with bolts.

[0007] As a further aspect of the present invention: first heat dissipation fins are provided on both the left and right sides of the lower housing, second heat dissipation fins are provided on both the front and rear sides of the lower housing, and a connecting pipe is fixedly installed at the upper end of the lower housing. The connecting pipe is connected to the first heat exchange pipe.

[0008] As a further aspect of the present invention: a liquid inlet is provided on the upper left side of the lower housing, and a liquid outlet is provided on the lower right side of the lower housing.

[0009] As a further aspect of the present invention: third heat dissipation fins are provided on both the left and right sides of the upper housing, and heat dissipation grooves are respectively opened at the front end of the upper housing; A filter screen is detachably installed on the inner side of the heat dissipation slot for filtering the air.

[0010] As a further embodiment of the present invention: an air inlet flange pipe is fixedly installed at the upper end of the upper shell, and the air inlet flange pipe is connected in a through manner to the second heat exchange pipe; The lower end of the upper shell is provided with a protruding tube, which engages with the connecting tube.

[0011] As a further aspect of the present invention: the rear end of the upper housing is threadedly connected to a mounting frame, and a fan is installed on the inner side of the mounting frame for air cooling of the second heat exchange tube.

[0012] As a further aspect of the present invention: the lower end of the lower shell is provided with a vent valve that is connected in communication with the first heat exchange tube, the lower end of the vent valve is provided with a first one-way valve, and the lower end of the first one-way valve is provided with a first exhaust pipe.

[0013] As a further aspect of the present invention: a bend is provided on the left side of the vent valve, a second one-way valve is provided at the left end of the bend, and a second exhaust pipe connected to the filter is provided at the left end of the second one-way valve.

[0014] As a further aspect of the present invention: the vent valve is connected in a continuous manner to the bend pipe, and the bend pipe is located in the middle of the left end of the vent valve and is bent.

[0015] The beneficial effects of this invention are: 1. By connecting and integrating two physical adsorption processes, room temperature adsorption and temperature-switching adsorption (TSA), targeting different impurities, a composite purification route with complementary advantages is formed, achieving a broad-spectrum and deep purification effect that is difficult to achieve with a single process. The system employs a dual-tower regeneration system with one tower for backup and one tower for operation. It achieves efficient regeneration through a complete closed-loop circuit that includes a heater, cooler, filter, and booster. This not only ensures the continuity of the production process but also greatly improves the utilization efficiency of the adsorbent and the overall energy efficiency of the device, thus resolving the contradiction between continuous operation and energy consumption control. An online analyzer and an automatic feedback control mechanism were introduced into the purified outlet pipeline, upgrading the traditional "blind operation" to a real-time quality monitoring and assurance system. This achieved a qualitative leap from "intermittent testing" to "full controllability," ensuring the absolute quality of the products. Attached Figure Description

[0016] The invention will now be further described with reference to the accompanying drawings.

[0017] Figure 1 This is a schematic diagram of the process flow of the present invention; Figure 2 This is a schematic diagram of the overall structure of the present invention; Figure 3 This is a schematic cross-sectional view of the overall structure of the present invention; Figure 4 This is a schematic diagram of the overall exploded structure of the lower shell of the present invention; Figure 5 This is a schematic diagram of the overall exploded structure of the upper shell of the present invention.

[0018] In the diagram: 1. Nitrogen inlet; 2. Desulfurization tower; 3. Carbon removal tower A; 4. Carbon removal tower B; 5. Nitrogen outlet; 6. Heater; 7. Flow meter; 8. Cooler; 801. Lower shell; 8011. First heat dissipation fin; 8012. Second heat dissipation fin; 8013. Connecting pipe; 8014. First heat exchange tube; 8015. Liquid inlet; 8016. Liquid outlet; 802. Upper shell; 8021. Third heat dissipation fin; 8022. Inlet flange pipe; 8023. Second heat exchange tube; 8024. Heat dissipation trough; 8025. Filter screen; 8026. Mounting frame; 8027. Fan; 803. Bolt; 9. Exhaust valve; 901. First check valve; 902. First exhaust pipe; 903. Bend; 904. Second check valve; 905. Second exhaust pipe; 10. Filter; 11. Booster. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] Please seeFigures 1-5 As shown, the present invention is a nitrogen refining and purification device and process.

[0021] Example 1 Please see Figure 1 The present invention provides a technical solution: a nitrogen refining and purification device and process, comprising two main stages: Phase 1: Adsorption and purification phase; Phase Two: Regeneration Phase; Phase One is the core production stage of the unit, which aims to purify raw nitrogen into high-purity nitrogen in one step. It includes the following steps: Step 1: Raw material nitrogen input and pretreatment: Ordinary nitrogen gas (usually with a purity of 99.99% or lower, i.e., level 4) from PSA nitrogen generators or air separation units is used as raw material gas and enters this purification unit through pipelines. A pressure regulating valve and flow meter are installed at the system inlet to stabilize the inlet pressure and monitor the processing gas volume, ensuring that the subsequent adsorption tower can operate stably under the design conditions. Step 2: Adsorption and removal of sulfides at room temperature: The raw nitrogen gas first enters the desulfurization tower 2, which is filled with a room-temperature adsorbent that has high selectivity and high adsorption capacity for sulfides such as hydrogen sulfide and sulfur dioxide, such as activated carbon, zinc oxide or special molecular sieves. In this step, trace amounts of sulfide impurities in the nitrogen gas are efficiently adsorbed and retained. This step is crucial because sulfides are usually catalyst poisons. If they enter the subsequent TSA unit, they may poison and deactivate the carbon removal adsorbent, shortening its service life. The desulfurization tower 2 is usually designed as a dual tower, which can be switched and regenerated periodically to ensure continuous operation. Step 3: Temperature Variable Adsorption (TSA) for deep removal of carbon compounds: After desulfurization, the nitrogen gas enters either carbon removal tower A3 or carbon removal tower B4, which is currently performing adsorption, according to the path set by the system. The tower is filled with special molecular sieves that have a strong adsorption capacity for carbon dioxide, carbon monoxide, and hydrocarbons. At room temperature or lower temperature, the molecules of these impurity gases are selectively adsorbed by the pore structure of the molecular sieves, while nitrogen molecules, which are relatively large, pass through smoothly. This process achieves deep removal of carbon compounds from the nitrogen gas. The two carbon removal towers adopt a "one standby, one in use" mode, that is, when one tower is performing adsorption, the other tower is in regeneration or standby mode, thereby realizing continuous operation of the device. Step 4: High-purity nitrogen production and monitoring: After being purified by the above two-stage adsorption, the nitrogen flows out from the carbon removal tower and reaches nitrogen outlet 5. An online analyzer (ATO1, such as a non-dispersive infrared gas analyzer) is installed on the outlet pipeline to monitor the carbon dioxide and carbon monoxide content in the final product gas in real time. Once the monitored value exceeds the preset strict standard, the control system will immediately trigger an alarm and automatically open the vent valve 9 to guide the unqualified nitrogen to the flare or vent pipe, ensuring that only qualified high-purity nitrogen is delivered to the downstream gas consumption point. In Phase Two, when the adsorbent in the carbon removal tower A3 becomes saturated, the system automatically switches to the carbon removal tower B4 for adsorption. Simultaneously, a regeneration program is initiated in the saturated carbon removal tower A3 to restore its adsorption capacity. The regeneration process is essentially the reverse of adsorption, using heating and purging to desorb impurities. The regeneration path is: Nitrogen Inlet 1 → Desulfurization Tower 2 → Carbon Removal Tower B4 → Flow Meter 7 → Heater 6 → Carbon Removal Tower A3 → Cooler 8 → Filter 10 → Booster 11 → Nitrogen Inlet 1. The process flow includes the following steps: Step 1: Preparation and heating of purge gas: Nitrogen inlet 1 → Desulfurization tower 2 → Carbon removal tower B4 → Flow meter 7 → Heater 6 The system draws out a portion of the raw nitrogen (or uses a portion of the pure nitrogen produced by another tower as a preferred purge gas), which is precisely metered by the flow meter 7 and then enters the heater 6, which is usually an electric heater, to heat this portion of purge gas to a predetermined temperature (e.g., 150°C-300°C). High temperature is the key to reducing the adsorption force of the adsorbent on impurities and desorbing them. Step 2: Hot purge desorption and impurity removal: Heater 6 → Carbon Removal Tower A3 High-temperature nitrogen gas enters the carbon removal tower A3 to be regenerated from the bottom of the tower in a counter-current (or forward) direction. The heat is transferred to the saturated adsorbent bed, which enables the adsorbed impurities such as carbon dioxide, carbon monoxide, and hydrocarbons to gain energy, desorb from the active sites of the adsorbent, turn back into gas, and be carried out of the adsorption tower by the high-temperature nitrogen gas flow. Step 3: Cooling and Purification Carbon removal tower A3 → Cooler 8 → Filter 10 After the hot purge gas containing high concentrations of impurities is discharged from the carbon removal tower A3, it enters the cooler 8 and is cooled to near ambient temperature. Subsequently, the gas passes through the filter 10, which may capture trace amounts of dust generated during the regeneration process and protect downstream equipment. Step 4: Purge gas recirculation or emission: Filter 10 → Booster 11 → Nitrogen Inlet 1 or Filter 10 → Exhaust Valve 9 There are two ways to treat the cooled and purified gas: 1. Recycling: After being pressurized by the booster 11, it is returned to the nitrogen inlet 1, mixed with the raw material gas, and then participates in the process again, which can reduce nitrogen consumption and improve the recovery rate; 2. Direct discharge: When the impurity concentration is too high or it is not suitable for reuse, the regeneration waste gas is directly discharged into the atmosphere or waste gas treatment system through the vent valve 9. In the later stage of regeneration, when the tower temperature drops to the predetermined value and the impurity content in the blown gas meets the standard, the regeneration stage ends and the carbon removal tower enters the standby state, ready for the next switching adsorption.

[0022] Example 2 Please see Figure 2 , Figure 3 , Figure 4 and Figure 5 In this invention, a technical solution is provided: the cooler 8 is composed of a lower shell 801 and an upper shell 802, and a bolt 803 is threadedly connected at the connection between the lower shell 801 and the upper shell 802.

[0023] Furthermore, first heat dissipation fins 8011 are provided on both the left and right sides of the lower housing 801, second heat dissipation fins 8012 are provided on both the front and rear sides of the lower housing 801, and a connecting pipe 8013 is fixedly installed at the upper end of the lower housing 801. The connecting pipe 8013 is connected to the first heat exchange tube 8014.

[0024] Furthermore, a liquid inlet 8015 is provided on the upper left side of the lower housing 801, and a liquid outlet 8016 is provided on the lower right side of the lower housing 801.

[0025] Furthermore, third heat dissipation fins 8021 are provided on both the left and right sides of the upper housing 802, and heat dissipation grooves 8024 are respectively opened at the front end of the upper housing 802. A filter 8025 is detachably installed on the inside of the heat sink 8024 for filtering the air.

[0026] Furthermore, an air inlet flange pipe 8022 is fixedly installed at the upper end of the upper shell 802, and the air inlet flange pipe 8022 is connected to the second heat exchange pipe 8023. The lower middle part of the upper housing 802 is provided with a protruding tube, which engages with the connecting pipe 8013.

[0027] Furthermore, the rear end of the upper housing 802 is threadedly connected to a mounting frame 8026, and a fan 8027 is installed on the inner side of the mounting frame 8026 for air cooling of the second heat exchange tube 8023.

[0028] Specifically, the first heat exchange tube 8014 is first installed inside the lower housing 801, and the second heat exchange tube 8023 is installed inside the upper housing 802. The lower housing 801 is then threadedly connected to the upper housing 802 using bolts 803. The inlet flange pipe 8022 at the upper end of the upper housing 802 is connected to the outlet pipes of the decarbonization towers A3 and B4. When nitrogen gas enters the second heat exchange tube 8023 through the inlet flange pipe 8022, the fan 8027 installed inside the mounting frame 8026 is turned on, drawing air from the outside and blowing it into the upper housing 802, thus stimulating the second heat exchange tube. The nitrogen flowing through the second heat exchange tube 8023 is cooled by air. The heat dissipation groove 8024 connected to the filter screen 8025 is opened at the front end of the upper shell 802, which allows the generated heat to be dissipated from the upper shell 802. When there is less nitrogen flowing through the second heat exchange tube 8023, the fan 8027 can be turned off to stop operation. At this time, the air flows naturally through the opening of the mounting frame 8026 and is discharged from the filter screen 8025. The third heat dissipation fins 8021 are installed on the outer sides of both the left and right ends of the upper shell 802, which can provide auxiliary heat dissipation when the heat inside the upper shell 802 is too high.

[0029] When nitrogen gas in the second heat exchange tube 8023 flows from the upper shell 802 into the lower shell 801, the lower shell 801 is fixedly equipped with a connecting pipe 8013 at its upper end, and the lower shell 801 is engaged with the lower middle part of the upper shell 802 through the connecting pipe 8013. At this time, nitrogen gas will enter the first heat exchange tube 8014 from the second heat exchange tube 8023. Then, the liquid inlet 8015 is connected to the condensate pipe, allowing condensate to enter the lower shell 801. After cooling the nitrogen gas in the first heat exchange tube 8014 again, it can be discharged from the liquid outlet 8016. With the first heat dissipation fins 8011 and the second heat dissipation fins 8012 installed at the front, rear, left and right ends of the lower shell 801 respectively, heat can be dissipated from the condensate to improve the overall cooling effect of the cooler 8. Finally, the condensate is discharged from the drain valve 9.

[0030] Example 3 This embodiment is derived based on Embodiment 2. Please refer to [link / reference]. Figure 1 , Figure 2 , Figure 3 and Figure 4 In this invention, a technical solution is provided: a vent valve 9 is provided at the lower end of the lower shell 801 and is connected in communication with the first heat exchange tube 8014; a first check valve 901 is provided at the lower end of the vent valve 9; and a first exhaust pipe 902 is provided at the lower end of the first check valve 901.

[0031] Furthermore, a bend 903 is provided on the left side of the vent valve 9, a second check valve 904 is provided at the left end of the bend 903, and a second exhaust pipe 905 connected to the filter 10 is provided at the left end of the second check valve 904.

[0032] Furthermore, the vent valve 9 is connected to the bend 903, which is located in the middle of the left end of the vent valve 9 and is bent.

[0033] Specifically, in embodiment two, when the cooled nitrogen enters the vent valve 9, the second check valve 904 can be closed first. If the nitrogen is not qualified, the first check valve 901 can be opened to directly discharge the unqualified nitrogen from the first exhaust pipe 902 into the trench. If the nitrogen is qualified, the first check valve 901 can be closed, allowing the nitrogen to flow along the vent valve 9 to the bend pipe 903. Finally, the second check valve 904 is opened and discharged into the filter 10 through the second exhaust pipe 905.

[0034] The bend 903 is located at the left end of the vent valve 9 and is bent. According to the direction of nitrogen discharge, it will first pass through the lower end of the vent valve 9 and then flow upward, and be discharged to the left from the bend 903.

[0035] The foregoing has provided a detailed description of one embodiment of the present invention, but this description is merely a preferred embodiment and should not be construed as limiting the scope of the invention. All equivalent variations and modifications made within the scope of the claims of this invention should still fall within the patent coverage of this invention.

Claims

1. A nitrogen refining and purification process, characterized in that, It includes the following steps: Step 1, Desulfurization Pretreatment: Ordinary nitrogen gas enters from the nitrogen inlet and passes through the desulfurization tower to remove sulfides such as H2S and SO2; Step 2, TSA deep carbon removal: The nitrogen gas after desulfurization enters the working carbon removal tower A or carbon removal tower B for deep removal of CO2, CO, and hydrocarbons; Step 3, Purity Monitoring and Output: The purified nitrogen is tested by an analyzer. If qualified high-purity nitrogen is generated, it is output. If it is not qualified, it is automatically vented. Step 4, Regeneration Purging and Heating: A portion of the nitrogen gas is drawn out and passed through a flow meter and heater to generate high-temperature regenerated nitrogen gas; Step 5, thermal purging and impurity desorption: High-temperature regenerated nitrogen gas is introduced in reverse into saturated carbon removal tower A or carbon removal tower B, and the desorbed impurities are carried out by heating. Step 6, Cooling and System Reset: The hot regenerated nitrogen containing impurities needs to be cooled by a cooler and then filtered by a filter. Finally, it is pressurized by a booster and then recycled or vented using a vent valve.

2. The nitrogen refining and purification apparatus according to claim 1, characterized in that, The cooler consists of a lower housing and an upper housing, and the connection between the lower housing and the upper housing is threaded with bolts.

3. The nitrogen refining and purification apparatus according to claim 2, characterized in that, The lower housing is provided with first heat dissipation fins on both the left and right sides, and second heat dissipation fins on both the front and rear sides. The upper end of the lower housing is fixedly installed with a connecting pipe. The connecting pipe is connected to the first heat exchange pipe.

4. The nitrogen refining and purification apparatus according to claim 2, characterized in that, A liquid inlet is provided on the upper left side of the lower housing, and a liquid outlet is provided on the lower right side of the lower housing.

5. The nitrogen refining and purification apparatus according to claim 2, characterized in that, The upper housing is provided with third heat dissipation fins on both the left and right sides, and heat dissipation grooves are respectively opened at the front end of the upper housing. A filter screen is detachably installed on the inner side of the heat dissipation slot for filtering the air.

6. The nitrogen refining and purification apparatus according to claim 5, characterized in that, An air inlet flange pipe is fixedly installed at the upper end of the upper shell, and the air inlet flange pipe is connected to the second heat exchange pipe. The lower end of the upper shell is provided with a protruding tube, which engages with the connecting tube.

7. A nitrogen refining and purification apparatus according to claim 5, characterized in that, The rear end of the upper housing is threadedly connected to a mounting frame, and a fan is installed on the inner side of the mounting frame for air cooling of the second heat exchange tube.

8. A nitrogen refining and purification apparatus according to claim 2, characterized in that, The lower end of the lower shell is provided with a vent valve that is connected in communication with the first heat exchange tube. The lower end of the vent valve is provided with a first check valve, and the lower end of the first check valve is provided with a first exhaust pipe.

9. A nitrogen refining and purification apparatus according to claim 8, characterized in that, A bend is provided on the left side of the vent valve, and a second check valve is provided at the left end of the bend. A second exhaust pipe connected to the filter is provided at the left end of the second check valve.

10. A nitrogen refining and purification apparatus according to claim 8, characterized in that, The vent valve is connected to the bend pipe, which is located in the middle of the left end of the vent valve and is bent.

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